Republican presidential nominee Donald Trump's support has sharply fallen in Utah where a poll on Wednesday showed him tied with Democrat Hillary Clinton in a state that has voted Republican in presidential races for decades.

The survey of 500 people from Salt Lake City-based Y2 Analytics also showed a surge for Evan McMullin, an ex-CIA officer running as an independent.

Trump and Clinton were both at 26 percent while McMullin, a member of the Mormon faith that dominates in Utah, trailed just behind at 22 percent.

The telephone poll of likely voters was conducted on Monday and Tuesday, after a video featuring comments from Trump about groping women surfaced last week.

The survey underscored the level of disaffection some conservatives have shown for Trump, who has found himself at odds with much of the Republican Party establishment.

The last time a Republican presidential nominee lost in Utah was in the landslide national election victory of President Lyndon Johnson, a Democrat, in 1964.

"There's limits to partisanship even in Utah of all places," Scott Riding, managing partner of Y2 Analytics, said.

The poll results indicate severe erosion in Trump's popularity in Utah even as Clinton's support has grown slightly. A Salt Lake Tribune poll in September put support for Trump at 34 percent, compared with 25 percent for Clinton.

A number of prominent Utah Republicans, including Governor Gary Herbert and U.S. Senator Mike Lee, pulled their support for Trump or called on him to quit the race.

McMullin, a former CIA counter-terrorism specialist and investment banker whose campaign is based in Utah, is less well known nationally than the other minor candidates, Green Party nominee Jill Stein and Libertarian Party nominee Gary Johnson.

Johnson ranked fourth in the Y2 Analytics poll with support from 14 percent of likely voters, roughly in line with his previous level of support in Utah.

McMullin, who is running as a conservative independent, is on the ballot in a dozen states including Utah, with plans to expand his reach before the Nov. 8 election, according to his campaign spokesman Rick Wilson.

The vast majority of participants in the poll were familiar with the video tape of Trump's vulgar comments about women during a 2005 recording and a third of them said it lowered their opinion of the New York businessman.